Semiconductor device and method for manufacturing the same

ABSTRACT

A semiconductor device includes a predetermined number of leads, a semiconductor element electrically connected to the leads and supported by one of the leads, and a sealing resin that covers the semiconductor element and a part of each lead. Each lead includes some portions exposed from the sealing resin. A surface plating layer is formed on at least one of the exposed portions of the respective leads.

FIELD

The present disclosure relates to a semiconductor device and a methodfor manufacturing a semiconductor device.

BACKGROUND

Conventional semiconductor devices incorporating semiconductor elementssuch as transistors are available on the market in variousconfigurations. For example, a semiconductor device may include asemiconductor element, a plurality of leads and a sealing resin. Theincorporated semiconductor element is mounted on one of the leads andelectrically connected to all the leads. The sealing resin covers thesemiconductor element and a part of each lead. The exposed portions ofthe respective leads provide terminals to be bonded to e.g., a printedcircuit board by soldering for example.

Depending on the specifications and/or usage environment of thesemiconductor device, a certain degree of stress may occur in the solderapplied between the terminals and the circuit board. Unfavorably suchstress may cause the solder to crack or even come off the bondinglocation.

SUMMARY

The present disclosure has been proposed under the above circumstances,and an object thereof is to provide a semiconductor device that isattachable to e.g., a printed circuit board with greater mountingstrength than is conventionally possible.

According to an aspect of the present disclosure, there is provided asemiconductor device provided with at least one lead, a semiconductorelement, and a sealing resin. The lead includes an obverse surface and areverse surface that are spaced apart from each other in a thicknessdirection of the device. The semiconductor element, such as a transistorfor example, is electrically connected to the lead. The sealing resincovers the semiconductor element and a part of the lead. The leadincludes portions exposed from the sealing resin, and at least one ofthe exposed portions is formed with a surface plating layer.

According to another aspect of the present disclosure, there is provideda method for making a semiconductor device of the above-noted aspect ofthe disclosure. In accordance with the method, the following steps maybe performed. A lead frame is prepared, which includes an obversesurface and a reverse surface that are spaced apart from each other in athickness direction of the semiconductor device. A semiconductor elementis mounted on the obverse surface of the lead frame. A sealing resin isformed to cover the semiconductor element and a part of the lead frame.By substitutional electroless plating, a surface plating layer is formedat least on a part of exposed portions of the lead frame that areexposed from the sealing resin.

Other features and advantages of the present disclosure will becomeapparent from the detailed description given below with reference to theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view showing a semiconductor device according to afirst embodiment of the present disclosure;

FIG. 2 is a front view showing the semiconductor device according to thefirst embodiment of the present disclosure;

FIG. 3 is a bottom view showing the semiconductor device according tothe first embodiment of the present disclosure;

FIG. 4 is a rear view showing the semiconductor device according to thefirst embodiment of the present disclosure;

FIG. 5 is a left-side view showing the semiconductor device according tothe first embodiment of the present disclosure;

FIG. 6 is a right-side view showing the semiconductor device accordingto the first embodiment of the present disclosure;

FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. 1;

FIG. 8 is a partially enlarged cross-sectional view taken along lineVII-VII in FIG. 1;

FIG. 9 is a cross-sectional view taken along line IX-IX in FIG. 1;

FIG. 10 is a plan view showing a method for manufacturing thesemiconductor device according to the first embodiment of the presentdisclosure;

FIG. 11 is a plan view showing the method for manufacturing thesemiconductor device according to the first embodiment of the presentdisclosure;

FIG. 12 is a partially enlarged cross-sectional view showing the methodfor manufacturing the semiconductor device according to the firstembodiment of the present disclosure;

FIG. 13 is a partially enlarged cross-sectional view showing asemiconductor device according to a second embodiment of the presentdisclosure;

FIG. 14 is a partially enlarged cross-sectional view showing a variationof the semiconductor device according to the second embodiment of thepresent disclosure;

FIG. 15 is a front view showing a semiconductor device according to athird embodiment of the present disclosure;

FIG. 16 is a bottom view showing the semiconductor device according tothe third embodiment of the present disclosure;

FIG. 17 is a rear view showing the semiconductor device according to thethird embodiment of the present disclosure;

FIG. 18 is a left-side view showing the semiconductor device accordingto the third embodiment of the present disclosure;

FIG. 19 is a right-side view showing the semiconductor device accordingto the third embodiment of the present disclosure;

FIG. 20 is a cross-sectional view taken along line XX-XX in FIG. 16;

FIG. 21 is a cross-sectional view taken along line XXI-XXI in FIG. 16;

FIG. 22 is a plan view showing a method for manufacturing thesemiconductor device according to the third embodiment of the presentdisclosure;

FIG. 23 is a plan view showing a method for manufacturing thesemiconductor device according to the third embodiment of the presentdisclosure;

FIG. 24 is a partial cross-sectional view taken along line XXIV-XXIV inFIG. 23;

FIG. 25 is a partial cross-sectional view showing a step subsequent tothe step of FIG. 24;

FIG. 26 is a partial cross-sectional view showing a step subsequent tothe step of FIG. 25;

FIG. 27 is a plan view showing a semiconductor device according to afourth embodiment of the present disclosure;

FIG. 28 is a plan view showing the semiconductor device according to thefourth embodiment of the present disclosure;

FIG. 29 is a front view showing the semiconductor device according tothe fourth embodiment of the present disclosure;

FIG. 30 is a bottom view showing the semiconductor device according tothe fourth embodiment of the present disclosure;

FIG. 31 is a rear view showing the semiconductor device according to thefourth embodiment of the present disclosure;

FIG. 32 is a left-side view showing the semiconductor device accordingto the fourth embodiment of the present disclosure; and

FIG. 33 is a left-side view showing the semiconductor device accordingto the fourth embodiment of the present disclosure.

DESCRIPTION OF EMBODIMENTS

Embodiments of the present disclosure will now be described withreference to the accompanying drawings.

FIGS. 1 through 9 show a semiconductor device according to a firstembodiment of the present disclosure. The illustrated semiconductordevice A1 includes three sorts of leads 1-3, a semiconductor element 4,and a sealing resin 6. In FIGS. 2 to 6, the dotted areas indicateplating layers 191, 291, 391 to be described below.

The semiconductor device A1 is not particularly limited in size. In thisembodiment, the semiconductor device A1 may have dimensions of 1.8 mm to2.6 mm in the x direction, 1.8 mm to 2.6 mm in the y direction, and 0.7mm to 1.0 mm in the z direction.

The leads 1, 2, and 3 are electrically connected to the semiconductorelement 4. Hereinafter, the leads 1, 2, and 3 are respectively referredto as a first wire-bonding lead 1, a second wire-bonding lead 2, and aprimary lead 3. The first wire-bonding lead or first lead 1, the secondwire-bonding lead or second lead 2, and the primary lead 3 may be formedby punching or bending a metal plate, for example. The first lead 1, thesecond lead 2, and the primary lead 3 are made of metal, preferably Cu,Ni, an alloy of these metals, or Alloy 42, for example. In the presentembodiment, the three leads 1, 2 and 3 are made of Cu. The leads 1-3 mayhave a thickness of 0.08 mm to 0.3 mm for example, and in the presentembodiment each lead has a thickness of about 0.125 mm.

As shown in FIG. 1, the first lead 1 and the second lead 2 are alignedin the x direction. The primary lead 3 is spaced apart from the firstlead 1 and the second lead 2 in the y direction. As viewed in the zdirection (in other words, in the thickness direction or in plan view),the primary lead 3 is the greatest in size among all the three leads,and the first lead 1 is the smallest.

The first lead 1 has an obverse surface 101, a reverse surface 102, anda reverse-side recess 180. The obverse surface 101 and the reversesurface 102 are spaced apart and face away from each other in the zdirection. The reverse-side recess 180 is a portion of the first lead 1which is recessed upward from the reverse surface 102 in the zdirection. The first lead 1 has a terminal portion 110 and a connectingportion 120.

As viewed in the z direction, the terminal portion 110 is provided at aposition avoiding the reverse-side recess 180 and has a rectangularshape. The terminal portion 110 has a terminal end face 111 and aterminal reverse surface 112. The terminal end face 111 faces in the xdirection and is exposed from the sealing resin 6. The terminal reversesurface 112 is apart of the reverse surface 102 of the lead 1, and isexposed from the sealing resin 6.

The connecting portion 120 is included in a range of the reverse-siderecess 180 as viewed in the z direction. In other words, the entirety ofthe connecting portion 120 overlaps with the reverse-side recess 180 asviewed in the z direction. The connecting portion 120 has a connectingend face 121. The connecting end face 121 faces in the y direction andis exposed from the sealing resin 6.

A first plating layer 191 is formed on the first lead 1 except for theparts covered with the sealing resin 6. Specifically, the first platinglayer is formed on all parts of the first lead 1 that are exposed fromthe sealing resin 6. Thus, in the present embodiment, the first platinglayer 191 is formed on the terminal end face 111 and the terminalreverse surface 112 of the terminal portion 110 and on the connectingend face 121 of the connecting portion 120. The first plating layer 191is made of a material having a higher solder wettability than the firstlead 1, and more specifically, than the base material of the lead 1.Here, the base material of a lead may refer to the main ingredient ofthe material forming the lead. When the lead is made of only a singlesubstance or element (Cu, for example), this single substance is thebase material. In the present embodiment, the first plating layer 191may be made of Au. The first plating layer 191 may be formed bysubstitutional electroless plating, which is performed in amanufacturing method described below.

The second lead 2 has an obverse surface 201, a reverse surface 202, anda reverse-side recess 280. The obverse surface 201 and the reversesurface 202 are spaced part and face away from each other in the zdirection. The reverse-side recess 280 is a portion of the second lead 2which is recessed upward from the reverse surface 202 in the zdirection. The second lead 2 has a terminal portion 210, connectingportions 220, and a wire-bonding portion 230.

As viewed in the z direction, the terminal portion 210 is provided at aposition avoiding the reverse-side recess 280 and has a rectangularshape. The terminal portion 210 has a terminal end face 211 and aterminal reverse surface 212. The terminal end face 211 faces in the xdirection and is exposed from the sealing resin 6. The terminal reversesurface 212 is apart of the reverse surface 202 of the lead 2, and isexposed from the sealing resin 6.

The connecting portions 220 are included in a range of the reverse-siderecess 280 as viewed in the z direction. Each connecting portion 220 hasa connecting end face 221. The connecting end face 221 faces in the ydirection and is exposed from the sealing resin 6.

As viewed in the z direction, the wire-bonding portion 230 of the lead 2is surrounded by the reverse-side recess 280 and has a rectangularshape. The wire-bonding portion 230 has a reverse surface 232, which isa part of the reverse surface 202 of the lead 2 and is exposed from thesealing resin 6.

The second plating layer 291 is formed on the second lead 2 except forthe parts covered with the sealing resin 6, in other words, on all partsof the second lead 2 that are exposed from the sealing resin 6. Thus, inthe present embodiment, the second plating layer 291 is formed on theterminal end face 211 and the terminal reverse surface 212 of theterminal portion 210, the connecting end faces 221 of the connectingportions 220, and the reverse surface 232 of the wire-bonding portion230. The second plating layer 291 is made of a material having a highersolder wettability than the second lead 2, and more specifically, thanthe base material of the lead 2. In the present embodiment, the secondplating layer 291 may be made of Au. The second plating layer 291 isformed by substitutional electroless plating, which is performed in amanufacturing method described below.

The primary lead 3 has an obverse surface 301, a reverse surface 302,and a reverse-side recess 380. The obverse surface 301 and the reversesurface 302 are spaced apart and face away from each other in the zdirection. The reverse-side recess 380 is a portion of the primary lead3 which is recessed upward in the z direction from the reverse surface302. The primary lead 3 has terminal portions 310, connecting portions320, and an element bonding portion 330.

As viewed in the z direction, each of the terminal portions 310 isprovided at a position avoiding the reverse-side recess 380 and has arectangular shape. Each of the terminal portions 310 has a terminal endface 311 and a terminal reverse surface 312. The terminal end face 311faces in the x direction and is exposed from the sealing resin 6. Theterminal reverse surface 312 is a part of the reverse surface 302, andis exposed from the sealing resin 6.

The connecting portions 320 are included in a range of the reverse-siderecess 380 as viewed in the z direction. Each of the connecting portions320 has a connecting end face 321. The connecting end face 321 faces inthe y direction and is exposed from the sealing resin 6.

As viewed in the z direction, the element bonding portion 330 issurrounded by the reverse-side recess 380 and has a rectangular shape.The element bonding portion 330 has an element-bonding reverse surface332, which is a part of the reverse surface 302 and is exposed from thesealing resin 6.

The third plating layer 391 is formed on the primary lead 3 except forthe parts covered with the sealing resin 6, or in other words, on allparts of the primary lead 3 exposed from the sealing resin 6. In thepresent embodiment, the third plating layer 391 is formed on theterminal end faces 311 and terminal reverse surfaces 312 of the terminalportions 310, the third connecting end portions 321 of the connectingportions 320, and the element-bonding reverse surface 332 of the elementbonding portion 330. The third plating layer 391 is made of a materialhaving a higher solder wettability than the primary lead 3, and morespecifically, than the base material of the lead 3. In the presentembodiment, the third plating layer 391 is made of Au, for example. Thethird plating layer 391 is formed by substitutional electroless plating,which is performed in a manufacturing method described below.

The semiconductor element 4 is chosen to fulfill the electric functionsrequired for the semiconductor device A1. The type of the semiconductorelement 4 is not particularly limited. In the present embodiment, thesemiconductor element 4 may be a transistor and mounted on the primarylead 3. The semiconductor element 4 includes an element body 40, a firstelectrode 41, second electrodes 42, and a third electrode 43 opposite tothe first and the second electrodes.

The first electrode 41 and the second electrodes 42 are arranged on theupper surface of the element body 40 that faces the same side as theobverse surface 301 of the primary lead 3. The third electrode 43 (FIG.7) is arranged on the lower surface of the element body 40 that facesthe same side as the reverse surface 302. In the present embodiment, thefirst electrode 41 is a gate electrode, the second electrodes 42 aresource electrodes, and the third electrode 43 is a drain electrode.

The semiconductor device A1 has a first wire 51 and second wires 52. Thefirst wire 51 is connected to the first electrode 41 and the terminalportion 110 of the first lead 1. Each second wire 52 is connected to oneof the second electrodes 42 and the wire-bonding portion 230 of thesecond lead 2.

The third electrode 43 is connected to the element bonding portion 330of the primary lead 3 via a conductive bonding member or layer 49. Theconductive bonding member 49 bonds the third electrode 43 to the obversesurface 301 of the element bonding portion 330.

The sealing resin 6 covers parts of the first, second and primary leads1-3, the semiconductor element 4, the first wire 51, and the secondwires 52. The sealing resin 6 may be formed by a black epoxy resin.

The sealing resin 6 has an obverse surface 61, a reverse surface 62 andfour side surfaces 63 (or a single side surface 63 when the four flatsurfaces are considered as a continuous one surface). The obversesurface 61 and the reverse surface 62 are spaced apart and face awayfrom each other in the z direction. The obverse surface 61 faces thesame side as the obverse surface 101 of the first lead 1, and hence asthe obverse surface 201 of the second lead 2, and the obverse surface301 of the primary lead 3. The reverse surface 62 faces the same side asthe reverse surface 102 of the first lead 1, and hence as the reversesurface 202 of the lead 2, and the reverse surface 302 of the primarylead 3. Each of the sealing-resin side surfaces 63 is connected to theobverse surface 61 and the reverse surface 62, and faces either in the xdirection or the y direction.

In the present embodiment, the terminal end face 111 and the connectingend face 121 of the first lead 1 are flush with the sealing-resin sidesurface 63 of the sealing resin 6. Likewise, the terminal end face 211and the connecting end faces 221 of the second lead 2, and the terminalend faces 311 and the connecting end faces 321 of the primary lead 3 areflush with the sealing-resin side surface 63 of the sealing resin 6.Further, the terminal reverse surface 112 of the first lead 1, theterminal reverse surface 212 and the reverse surface 232 of the secondlead 2, and the terminal reverse surfaces 312 and the element-bondingreverse surface 332 of the primary lead 3 are flush with the reversesurface 62 of the sealing resin 6.

The following describes a method for manufacturing the semiconductordevice A1, with reference to FIGS. 10 to 12.

First, a lead frame 10 is prepared as shown in FIG. 10. The lead frame10 is a plate-like material that forms the first lead 1, the second lead2, and the primary lead 3. An obverse surface 1010 of the lead frame 10provides the obverse surface 101, the obverse surface 201, and theobverse surface 301. In FIG. 10, the sparsely hatched parts provide thereverse-side recess 180, the reverse-side recess 280, and thereverse-side recess 380. Further, the densely hatched parts provide theterminal portion 110, the terminal portion 210, the wire-bonding portion230, the terminal portions 310, and the element bonding portion 330. Inthe present embodiment, the base material of the lead frame 10 is Cu.

Next, as shown in FIG. 11, a semiconductor element 4 is bonded to theelement bonding portion 330 of the lead frame 10 with a conductivebonding member 49. Also, a first wire 51 is bonded to the firstelectrode 41 and the terminal portion 110, and second wires 52 arebonded to the second electrodes 42 and the wire-bonding portion 230.Next, a sealing material, which is not shown in the figure, is cured toform the sealing resin 6 (not shown) that covers a part of the leadframe 10, as well as the semiconductor element 4, the first wire 51, andthe second wires 52. In the present embodiment, the sealing resin 6 isformed on the entire region shown in FIG. 11. Next, the lead frame 10and the sealing resin 6 are cut along a cut line 81. In this way, apiece corresponding to the semiconductor device A1 is obtained.

Next, the first plating layer 191, the second plating layer 291, and thethird plating layer 391 are formed on the piece obtained by the cutting.In the present embodiment, the obtained piece is subjected tosubstitutional electroless plating whereby the piece is immersed in apredetermined plating solution. As a result, as seen from theillustration of FIG. 12 (featuring the primary lead 3 only for thepurpose of an example), Cu (the base material of the primary lead 3)becomes Cu ions (“lead base-material ions 3000”) and escape from theterminal end face 311 and the terminal reverse surface 312, which areexposed from the sealing resin 6. In turn, Au ions (“surface platingions 3910) included in the plating solution take place of the leadbase-material ions 3000 to be bound to the terminal end face 311 and theterminal reverse surface 312. The substitution between the leadbase-material ions 3000 and the surface plating ions 3910 causes a thirdplating layer 391 to form on the terminal end face 311 and the terminalreverse surface 312. In substitutional electroless plating, thesubstitution at a given portion will end when the lead base-materialions 3000 at the portion have been substituted by the surface platingions 3910. As such, the third plating layer 391 formed by substitutionalelectroless plating does not have a significant thickness that thatwould otherwise cause the surface of the primary lead 3 to undulyprotrude. Accordingly, even after the formation of the third platinglayer 391, the terminal end face 311 remains flush with thesealing-resin side surface 63, and the terminal reverse surface 312remains flush with the reverse surface 62.

In addition to the third plating layer 391, the first plating layer 191and the second plating layer 291 are also formed. Similarly to theabove, the first plating layer 191 and the second plating layer 291 donot have significant thicknesses that would cause the surfaces of thefirst lead 1 and the second lead 2 to protrude. Accordingly, even afterthe first plating layer 191 and the second plating layer 291 are formed,the terminal end face 111, the connecting end face 121, the terminal endface 211, and the connecting end faces 221 remain flush with thesealing-resin side surfaces 63, and, the terminal reverse surface 112,the terminal reverse surface 212, and the reverse surface 232 remainflush with the reverse surface 62.

These steps as described above are performed to form the semiconductordevice A1.

The following describes advantages of the semiconductor device A1 andthe method for manufacturing the device A1.

According to the present embodiment, the first plating layer 191, thesecond plating layer 291, and the third plating layer 391 are formed onall the exposed parts of the relevant leads 1, 2 and 3. Each platinglayer 191, 291 and 391 is made of a material having a higher solderwettability than the base material of the relevant lead 1, 2 and 3.Accordingly, when the semiconductor device A1 is to be mounted on e.g.,a circuit board by solder, the solder can be adhered to all the exposedparts of the leads 1-3, and this contributes to enhancing the bonding ormounting strength of the semiconductor device A1 to the circuit board.

The first plating layer 191, the second plating layer 291, and the thirdplating layer 391 are formed by substitutional electroless plating;therefore, in the piece divided out from the lead frame 10 shown in FIG.11, the first plating layer 191, the second plating layer 291, and thethird plating layer 391 are reliably formed on all parts of the firstlead 1, the second lead 2, and the primary lead 3 that are exposed fromthe sealing resin 6. This is preferable in enhancing the mountingstrength. Also, since substitutional electroless plating is employed,the first lead 1, the second lead 2, and the primary lead 3 do not needto have a shape electrically connectable to a plating electrode forelectrolytic plating. Furthermore, the first plating layer 191, thesecond plating layer 291, and the third plating layer 391 are not formedon the parts of the first lead 1, the second lead 2, and the primarylead 3 that are covered with the sealing resin 6. This is preferable inreducing the manufacturing cost of the semiconductor device A1.

The terminal end face 111, the connecting end face 121, the terminal endface 211, the connecting end faces 221, the terminal end faces 311, andthe connecting end faces 321 are flush with the sealing-resin sidesurfaces 63. As such, the first lead 1, the second lead 2, and theprimary lead 3 do not protrude from the sealing resin 6 as viewed in thez direction. This makes it possible to enhance the mounting strength ofthe semiconductor device while reducing the area necessary for mountingthe semiconductor device A1.

The terminal reverse surface 112, the terminal reverse surface 212, andthe terminal reverse surfaces 312 are flush with the reverse surface 62,and are provided with the first plating layer 191, the second platinglayer 291, and the third plating layer 391, respectively. In this way,the third plating layer 391 is formed on the terminal end faces 311 andthe terminal reverse surfaces 312, as shown in FIG. 8. This is suitablein reliably adhering solder in a continuous manner from the terminal endfaces 311 to the terminal reverse surfaces 312 when mounting thesemiconductor device A1.

FIGS. 13 to 33 show other embodiments of the present disclosure. Inthese figures, elements that are the same as or similar to those in theabove embodiments are indicated by the same reference signs as in theabove embodiment.

FIG. 13 shows a semiconductor device according to a second embodiment ofthe present disclosure. Regarding a semiconductor device A2 of thepresent embodiment, an intermediate plating layer 392 is formed on theprimary lead 3.

The intermediate plating layer 392 is formed on the obverse surface 301,the reverse surface 302, and the reverse-side recess 380. On the otherhand, the intermediate plating layer 392 is not formed on the terminalend faces 311 and the connecting end faces 321. This is because theintermediate plating layer 392 is formed on the upper and lower surfacesof the lead frame 10 shown in FIG. 10, and as such, the terminal endfaces 311 and the connecting end faces 321, which are formed by cuttingthe lead frame 10, are not provided with the intermediate plating layer392.

The intermediate plating layer 392 may be a laminate made up of a Niplating layer, a Pd plating layer, and a Au plating layer. The Niplating layer may have a thickness of 0.5 μm to 2.0 μm, the Pd platinglayer a thickness of 0.02 μm to 0.15 μm, and the Au plating layer athickness of 0.003 μm to 0.015 μm. Other examples of the intermediateplating layer 392 include a laminate made up of a Ni plating layer and aAu plating layer.

The intermediate plating layer 392 is provided between the terminalreverse surface 312 and the third plating layer 391. In this fashion,the Au layer of the intermediate plating layer 392 is assimilated intothe third plating layer 391.

The above embodiment also serves to enhance the mounting strength of thesemiconductor device A2.

FIG. 14 shows a variation of the semiconductor device A2. In the presentvariation, the first plating layer 191, the second plating layer 291 andthe third plating layer 391 are provided at different places or regionsthan those in the above-noted example.

As shown in the example of FIG. 14, the third plating layer 391 of theprimary lead 3 does not cover the intermediate plating layer 392 on theterminal reverse surface 312. The third plating layer 391 is formed onthe terminal end face 311 where the base material of the primary lead 3is exposed. The same holds for the first plating layer 191 and thesecond plating layer 291, which cover the terminal end face 111 and theterminal end face 211 but do not cover the terminal reverse surface 112or the terminal reverse surface 212. Such a variation can also enhancethe mounting strength of the semiconductor device A2.

FIGS. 15 to 21 show a semiconductor device according to a thirdembodiment of the present disclosure. A semiconductor device A3 of thepresent disclosure differs from the semiconductor devices A1 and A2 inthat the first plating layer 191, the second plating layer 291 and thethird plating layer 391 are formed at different places or regions thanthose of the above-noted example.

FIG. 15 is a front view showing the semiconductor device A3. FIG. 16 isa bottom view showing the semiconductor device A3. FIG. 17 is a rearview showing the semiconductor device A3. FIG. 18 is a left-side viewshowing the semiconductor device A3. FIG. 19 is a right-side viewshowing the semiconductor device A3. FIG. 20 is a cross-sectional viewtaken along line XX-XX of FIG. 16. FIG. 21 is a cross-sectional viewtaken along line XXI-XXI of FIG. 16. Note that the plan view showing thesemiconductor device A3 is the same as FIG. 1.

In the present embodiment, the first plating layer 191 and the secondplating layer 291 are not formed on the connecting end face 121 and theconnecting end faces 221, as shown in FIG. 15. The connecting end face121 and the connecting end faces 221 are not connected to the reversesurface 102 and the reverse surface 202.

Further, the third plating layer 391 is not formed on the connecting endfaces 321 shown in FIG. 17. The connecting end faces 321 are notconnected to the reverse surface 302.

On the other hand, the first plating layer 191 and the third platinglayer 391 are formed on the terminal end face 111 and the terminal endfaces 311, as shown in FIGS. 18 and 19. The terminal end face 111 andthe terminal end faces 311 are connected to the reverse surface 102 andthe reverse surface 302, respectively.

The sealing-resin side surface 63 shown in FIGS. 18 and 19 includes afirst portion 631 and a second portion 632. As shown in FIG. 20, thefirst portion 631 is located closer to the obverse surface 61 in the zdirection, and is located more outward, as viewed in the z direction,than the terminal end face 111 and the terminal end faces 311 on whichthe first plating layer 191 and the third plating layer 391 are formed.The second portion 632 is located closer to the reverse surface 62 thanthe first portion 631 in the z direction. The second portion 632 issmoothly connected to the terminal end face 111 and the terminal endfaces 311 on which the first plating layer 191 and the third platinglayer 391 are formed. An upper portion of the second portion 632 in thez direction forms a concave curved surface. The first portion 631 andthe second portion 632 are connected at an angle.

The following describes a method for manufacturing the semiconductordevice A3, with reference to FIGS. 22 to 26.

First, a lead frame 10 is prepared as shown in FIG. 22. This lead framehas the same structure as the lead frame 10 shown in FIG. 10, and has asize and shape that allows for manufacturing of a plurality ofsemiconductor devices A3.

Next, for each semiconductor device A3, a semiconductor element 4 isbonded to an element bonding portion 330 of the lead frame 10 with aconductive bonding member 49, as shown in FIGS. 23 and 24. Also, as withthe case shown in FIG. 11, a first wire 51 is bonded to a firstelectrode 41 and a terminal portion 110, and second wires 52 are bondedto second electrodes 42 and a wire-bonding portion 230. Next, a sealingmaterial, which is not shown in figures, is cured to thereby form asealing resin 60 (not shown) that covers a part of the lead frame 10, aswell as the semiconductor element 4, the first wire 51, and the secondwires 52. In the present embodiment, the sealing resin 60 is formed onthe entire region shown in FIG. 23.

Next, a slit 801 is formed as shown in FIGS. 23 and 25. The slit 801 isprovided between element bonding portions 330 that are adjacent to eachother in the x direction, and is elongated in the y direction. The slit801 is open at least at the side of the reverse surface 62. In theillustrated example, the slit 801 is open only at the side of thereverse surface 62, and does not reach the sealing-resin obverse surface61. Note that the depth of the slit 801 is greater than the thickness ofthe lead frame 10. As a result of the slit 801 being formed, a terminalend face 111 and terminal end faces 311 as shown in FIGS. 18 and 19 areformed.

Next, a first plating layer 191 and a third plating layer 391 are formedon the terminal end face 111 and the terminal end faces 311 which areexposed from the sealing resin 60 due to the slit 801. The first platinglayer 191 and the third plating layer 391 are formed in the same manneras in the method for manufacturing the semiconductor device A1 describedabove. Note that in this process, the first plating layer 191 and thethird plating layer 391 are also formed at the side of the reversesurface 62.

Next, as shown in FIGS. 23 and 26, the lead frame 10 and the sealingresin 60 are cut along a cut line 802 and a cut line 803. The cut line802 is parallel to the slit 801, narrower than the slit 801, andincluded in the slit 801 as viewed in the z direction. On the otherhand, the cut line 803 is located between element bonding portions 330adjacent to each other in the y direction, and extends along the xdirection. Cutting along these lines yields a plurality of semiconductordevices A3. Note that in each semiconductor device A3, the secondportion 632 is a trace of the slit 801, and the first portion 631 is atrace of the cut along the cut line 802. Also note that the firstplating layer 191, a second plating layer 291, and the third platinglayer 391 are not formed on a connecting end face 121, connecting endfaces 221, and connecting end faces 321 which are formed by the cutalong the cut line 803.

Such an embodiment can also enhance the mounting strength of thesemiconductor device A3. The connecting end face 121, the connecting endfaces 221, and the connecting end faces 321, which are not connected tothe reverse surface 102, the reverse surface 202, and the reversesurface 302, are not used as portions to be bonded by soldering or thelike when the semiconductor device A3 is mounted. Accordingly, althoughthe first plating layer 191, the second plating layer 291, and the thirdplating layer 391 is not formed on these portions, the mounting strengthof the semiconductor device A3 is unlikely to deteriorate.

In the state shown in FIG. 25, the lead frame 10 and the sealing resin60 are connected as a whole, and have no through-holes. Accordingly, thelead frame 10 and the sealing resin 60 maintain a high stiffness when,for example, the first plating layer 191, the second plating layer 291and the third plating layer 391 are formed, thus allowing themanufacturing process to be performed reliably and smoothly.

Also, when a plating solution is applied to the terminal end face 111and the terminal end faces 311 exposed at the slit 801 so as to form thefirst plating layer 191 and the third plating layer 391, the platingsolution can smoothly penetrate along the slit 801 by capillary action.

It is possible to manufacture the semiconductor device A3 by a method inwhich the slit 801 is formed to penetrate in the z direction. In thesemiconductor device A3 formed by this method, the sealing-resin sidesurfaces 63 are flat and do not have the first portions 631 and thesecond portions 632.

FIGS. 27 to 33 show a semiconductor device A4 according to a fourthembodiment of the present disclosure. FIG. 27 is a plan view showing thesemiconductor device A4. FIG. 28 is a plan view showing thesemiconductor device A4. FIG. 29 is a front view showing thesemiconductor device A4. FIG. 30 is a bottom view showing thesemiconductor device A4. FIG. 31 is a rear view showing thesemiconductor device A4. FIG. 32 is a left-side view showing thesemiconductor device according to the fourth embodiment of the presentdisclosure. FIG. 33 is a right-side view showing the semiconductordevice according to the fourth embodiment of the present disclosure. InFIG. 27 and FIGS. 29 to 33, dotted areas indicate a first plating layer191, a second plating layer 291, and a third plating layer 391.

In the present embodiment, a terminal portion 110, terminal portions210, terminal portions 310 and connecting portions 320 protrude from asealing resin 6 as viewed in the z direction. As with theabove-described embodiments, the first plating layer 191, the secondplating layer 291, and the third plating layer 391 are formed on allparts of a first wire-bonding lead 1, a second wire-bonding lead 2, anda primary lead 3 except for parts covered with the sealing resin 6, orin other words, on all parts of the first lead 1, the second lead 2, andthe primary lead 3 exposed from the sealing resin 6.

The terminal portion 110 has a terminal end face 111, a terminal reversesurface 112, and a terminal obverse surface 114. The terminal end face111 faces in the y direction. The terminal reverse surface 112 is a partof a reverse surface 102. The terminal obverse surface 114 is a part ofan obverse surface 101. The terminal reverse surface 112 and theterminal obverse surface 114 are connected by a pair of terminal sidesurfaces facing oppositely in the x direction. The first plating layer191 is formed on the terminal end face 111, the terminal reverse surface112, the terminal side surfaces, and the terminal obverse surface 114.

Each of the terminal portions 210 has a terminal end face 211, aterminal reverse surface 212, and a terminal obverse surface 214. Theterminal end face 211 faces in the y direction. The terminal reversesurface 212 is a part of the reverse surface 202 of the lead 2. Theterminal obverse surface 214 is a part of the obverse surface 201 of thelead 2. The terminal reverse surface 212 and the terminal obversesurface 214 are connected by a pair of terminal side surfaces of thelead 2 facing oppositely in the x direction. The second plating layer291 is formed on the terminal end face 211, the terminal reverse surface212, the terminal side surfaces, and the terminal obverse surface 214.

Each of the terminal portions 310 of the lead 3 has a terminal end face311, a terminal reverse surface 312, and a terminal obverse surface 314.The terminal end face 311 faces in the y direction. The terminal reversesurface 312 is a part of the reverse surface 302 of the lead 3. Theterminal obverse surface 314 is a part of the obverse surface 301 of thelead 3. The terminal reverse surface 312 and the terminal obversesurface 314 are connected by a pair of terminal side surfaces of thelead 3 facing oppositely in the x direction. The third plating layer 391is formed on the terminal end face 311, the terminal reverse surface312, the third terminal side surfaces, and the terminal obverse surface314.

Each of the connecting portions 320 of the lead 3 has a connecting endface 321, a connecting reverse surface 322, a pair of connecting sidesurfaces 323, and a connecting obverse surface 324. The connecting endface 321 faces in the x direction. The connecting reverse surface 322 isa part of the reverse surface 302 of the lead 3. The connecting obversesurface 324 is a part of the obverse surface 301 of the lead 3. Theconnecting side surfaces 323 connect the connecting reverse surface 322and the connecting obverse surface 324 and face in the y direction. Thethird plating layer 391 is formed on the connecting end face 321, theconnecting reverse surface 322, the connecting side surfaces, and theconnecting obverse surface 324.

Such an embodiment can also enhance the mounting strength of thesemiconductor device A4. As is evident from the present embodiment, theforming of the first to third plating layers 191, 291, 391 can alsoimprove the mounting strength of the device in which protruding portions(such as terminal portions 110, 210, 310, and connecting portions 320)from the sealing resin 6 are provided.

The semiconductor device according to the present disclosure and themethod for manufacturing the same are not limited to the embodimentsdescribed above. Various design changes can be made to the specificconfigurations of the semiconductor device and the method formanufacturing the same.

The invention claimed is:
 1. A semiconductor device comprising: at leastone lead including an obverse surface and a reverse surface that arespaced apart from each other in a thickness direction; a semiconductorelement supported by the lead; and a sealing resin covering thesemiconductor element and a part of the lead, the sealing resincomprising a sealing-resin side surface and a sealing-resin reversesurface, wherein the lead includes portions exposed from the sealingresin, the exposed portions include a first exposed portion and a secondexposed portion that are exposed at the sealing-resin side surface andthe sealing-resin reverse surface, respectively, the first exposedportion being flush with the sealing-resin side surface, and each of thefirst exposed portion and the second exposed portion is formed with asurface plating layer, the surface plating layer on the first exposedportion is formed integral with the surface plating layer on the secondexposed portion, the sealing resin comprises a sealing-resin obversesurface that is connected to the sealing-resin side surface, thesealing-resin side surface comprises a first portion and a secondportion, the first portion being outwardly offset from the secondportion as viewed in the thickness direction, and the first exposedportion of the lead is disposed at the second portion of thesealing-resin side surface.
 2. The semiconductor device according toclaim 1, wherein each of the exposed portions is formed with a surfaceplating layer.
 3. The semiconductor device according to claim 1, whereinthe surface plating layer has a higher solder wettability than a basematerial of the lead.
 4. The semiconductor device according to claim 3,wherein the base material comprises Cu.
 5. The semiconductor deviceaccording to claim 4, wherein the surface plating layer is made of Au.6. The semiconductor device according to claim 1, wherein the surfaceplating layer is formed by substitutional electroless plating.
 7. Thesemiconductor device according to claim 1, wherein at least a part ofthe surface plating layer is formed directly on a base material of thelead.
 8. The semiconductor device according to claim 7, wherein anentirety of the surface plating layer is formed directly on the basematerial of the lead.
 9. The semiconductor device according to claim 1,further comprising an intermediate plating layer disposed between thesurface plating layer and a bulk material of the lead.
 10. Thesemiconductor device according to claim 9, wherein the intermediateplating layer is formed near the obverse surface and the reverse surfaceof the lead.
 11. The semiconductor device according to claim 1, whereinthe lead comprises a terminal end face that is flush with thesealing-resin side surface.
 12. The semiconductor device according toclaim 11, wherein the reverse surface of the lead is flush with thesealing-resin reverse surface.
 13. The semiconductor device according toclaim 1, wherein the lead is formed with a reverse-side recess that isdisposed at the reverse surface of the lead and covered with the sealingresin.
 14. The semiconductor device according to claim 13, wherein thesemiconductor element is disposed at a position avoiding thereverse-side recess as viewed in the thickness direction.
 15. Thesemiconductor device according to claim 1, further comprising anadditional lead and a wire, wherein the additional lead includes anobverse surface and a reverse surface that are spaced apart from eachother in the thickness direction, the additional lead being formed witha reverse-side recess that is disposed at the reverse surface of theadditional lead and covered with the sealing resin, the wire having afirst end and a second end that are bonded to the semiconductor elementand the additional lead, respectively, wherein the second end of thewire is disposed at a position avoiding the reverse-side recess of theadditional lead as viewed in the thickness direction.
 16. Thesemiconductor device according to claim 1, wherein the sealing resincomprises a sealing-resin obverse surface that is connected to thesealing-resin side surface, and the lead comprises a terminal end faceexposed from the sealing-resin side surface and spaced apart from thereverse surface of the lead, no surface plating layer being formed onthe terminal end face.